2004 5.3 2wd pcm tune and heaers otherwise stock


Trans started to shift very hard 1-2 for a few days then would not shift just slipped unless I eased up on throttle and let it slide into gear ........fluid clean and up ....... 32 K daily driver not abused tow car trailer 7kgvw in summer never a problem , never overheated ........ this spring had shop install a Transgo HD-2 and vette / sonnex servo's .........

dropped the pan ......some springs from shift kit busted and the plastic pistons broken .....now in shop for rebuild

Hopefully they can give me an idea what caused the failure ....anybody here got any ideas

 

that may be why.

 

Maybe the 1-2 accumulator piston let go?

 

Yes it did , I had expected to drop the valve body and replace those parts but apparently the bands etc are used up too ...... could this have been a fualty shift kit install ? when you guys instll shift kits do you replace those plastic pistons with the metal ones ?I dont recall that the shift kit came with replacement pistons

 

That was my thought when I read the first post.

 

Sounds like the 1-2 accumulator piston cracked and burnt up the 2-4 band and drum. I would NEVER install a shift kit and reuse the stock plastic pistons. Always upgrade to the metal ones. It doesn't sound like a faulty shift kit install, it sounds like the piston just cracked and burnt it up.

 

There are GM aluminum pistons available as well as aftermarket pinless ones

 

Yes I knew that but did not think to do when only doing a shift kit ..............do most of you install the alum pistons when you do a shift kit for a stock engine daily driver ...........I know the trans shops do when they do a perf rebuild .......or was my experience not the norm and just got unlucky that the plastic ones let go .pbly not but would think would hear more failures after shift kit when plastic pistons left in trans ???